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Hello Everyone,

I see someone else has already posted about are uncomfortably hot weather here in Chicago over the past few days. Outside temps are in the upper 90s and it's pretty humid.

I'm having issues with my a/c not working properly on the 2nd floor. The first floor is comfortable. I think it's in the mid-70s. Now the upstairs is about 85-87 degrees and 50% humidity. It doesn't really matter what we set it at. Unless we set it for the temperature it already is (or MAYBE a few degrees cooler), it won't match. This happened last year as well, shortly after our A/C was installed.

Our house is a foreclosure and the previous tenants had ripped out the A/C. We had a company come out last year to intall two units. (My house is dual-zoned.) We have one furnace in the basement and one in the attic. Our A/C units are both outside.

All bedrooms upstairs have at least one return. Our master has two returns and four vents total. Two in the main part of the bedroom, one in the bathroom, and one in the closet. The hallway has a return and a vent but it is open to the stairwell. You can feel the temperature (and humidity) rise about ten degrees at a certain point on the stairs.

We keep our bedroom doors closed during the day to try to preserve whatever a/c we have in our room, but when we open the door to our room we are greeted with a face full of hot, stuffy, humid air. At 10 p.m. it's still 85 or so in our room. It feels awful. I had my husband measure the temps at the vent near our bed and the return and there was only about a 6 degree difference.

We had the HVAC installers come out a second time last year when it was apparent that our bedroom could not reach a comfortable level. They said everything looked fine and that you could only expect A/C to keep the house 10 degrees cooler than the temps outside; however, my parents and other people I know have no problems keeping their homes cool in the same climate.

Our ductwork is in the attic and it gets insanely hot up there. There are (gable? soffit?) vents up there, but I think they might be covered with insulation or maybe there aren't enough? All our ductwork is covered with insulation.

It just doesn't seem right that our dual-zoned HVAC cannot keep our 2nd floor comfortable. Does anybody have any recs?
 

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2nd Floor A/C Issue

Hello Everyone,

I see someone else has already posted about are uncomfortably hot weather here in Chicago over the past few days. Outside temps are in the upper 90s and it's pretty humid.

I'm having issues with my a/c not working properly on the 2nd floor. The first floor is comfortable. I think it's in the mid-70s. Now the upstairs is about 85-87 degrees and 50% humidity. It doesn't really matter what we set it at. Unless we set it for the temperature it already is (or MAYBE a few degrees cooler), it won't match. This happened last year as well, shortly after our A/C was installed.

Our house is a foreclosure and the previous tenants had ripped out the A/C. We had a company come out last year to intall two units. (My house is dual-zoned.) We have one furnace in the basement and one in the attic. Our A/C units are both outside.

All bedrooms upstairs have at least one return. Our master has two returns and four vents total. Two in the main part of the bedroom, one in the bathroom, and one in the closet. The hallway has a return and a vent but it is open to the stairwell. You can feel the temperature (and humidity) rise about ten degrees at a certain point on the stairs.

We keep our bedroom doors closed during the day to try to preserve whatever a/c we have in our room, but when we open the door to our room we are greeted with a face full of hot, stuffy, humid air. At 10 p.m. it's still 85 or so in our room. It feels awful. I had my husband measure the temps at the vent near our bed and the return and there was only about a 6 degree difference.

We had the HVAC installers come out a second time last year when it was apparent that our bedroom could not reach a comfortable level. They said everything looked fine and that you could only expect A/C to keep the house 10 degrees cooler than the temps outside; however, my parents and other people I know have no problems keeping their homes cool in the same climate.

Our ductwork is in the attic and it gets insanely hot up there. There are (gable? soffit?) vents up there, but I think they might be covered with insulation or maybe there aren't enough? All our ductwork is covered with insulation.

It just doesn't seem right that our dual-zoned HVAC cannot keep our 2nd floor comfortable. Does anybody have any recs?
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Thank you for the detailed description - that really helps...

There could be several reasons you are experiencing these problems. The following items should be checked by a competent A/C installation and repair company:

1. The attic insulation (amount and type)
2. The wall insulation
3. The ductwork installation and insulation
4. The sizing and performance of the installed A/C unit for the 2nd floor, as well as the distribution ductwork (is it corrugated, smooth, long runs, lots or elbows or flexduct?). Also check for ductwork leaks.
5. Your windows - are they insulated glass? (check all of them, but especially the 2nd floor)
6. Is the attic properly ventilated? Is there an attic fan?
7. Is the condensing unit located on the west or south side and exposed to the sun all day?
7. Make sure your A/C system is properly maintained (clean filters, condenser, etc)

Remember that when temps hit the mid to upper 90s, that usually stresses or exceeds and design capability of many A/C units, especially with elevated humidity. However, you should be able to achieve a reasonable comfort level if the system was properly designed and installed and your house factors were all considered.
 

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What is the temp of the air coming out of the vent? Surely it is much cooler than the six degrees of temp difference you mention?
 

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Call another company after you make sure all the ducts in the attic are connected and sealed. The first one is feeding you BS with an AC can only cool 10 degrees from outside temp so I wouldn't trust them with my system. It's been 98-100 here this week and my house is a comfortable 75 degrees . My customers would not tolerate 90 degree houses when it hits 100 outside and neither should you.
 

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KemoSabe
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As a rule of thumb, several different HVAC techs told me that supply air should average 20 degrees cooler than room temperature of the warmest room in the zone if the unit is operating efficiently.
 
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